Integrated circuits are made possible by processes which produce intricately patterned material layers on substrate surfaces. Layers are deposited and patterned on a substrate many, many times during production of a substrate of integrated circuits. Generally speaking, each layer deposits not only on the front of the substrate but also along the edge of the substrate. Leftover material around the edge can negatively impact downstream processes by complicating substrate handling and forming debris which may relocate to the front or back of the substrate. Debris on the front of the substrate directly impacts yield while debris on the back negatively impacts, e.g., the focus integrity during photolithography.
Substrate-scale masks cover the front of a substrate and allow any deposition on the edge of a substrate to be removed by etch processes. The substrate-scale mask is affixed to the interior of the processing chamber and moved towards the front of the substrate prior to the edge etch. Positioning of the substrate-scale mask determines the uniformity of the edge etch process along the perimeter of the substrate.
Therefore, a system and method is needed for aligning a substrate-scale mask to process the edge of a substrate.